This invention relates to throttle means for controlling the flow of liquid fuel for an internal combustion engine and for atomizing or breaking-up and mixing the fuel with air to effect a homogeneous dispersion of fine fuel droplets in a gaseous fuel-air mixture to facilitate complete evaporation of the fuel prior to combustion in the engine.
A primary object is to provide essentially symmetrical throttle means comprising a pair of throttle members such as an annulus or orifice member and a coaxial closure member relatively movable axially with respect to each other and shaped to vary the effective opening of the orifice member by the relative movement.
Another object is to provide such throttle means shaped to comprise a variable restriction diffuser for effecting gas flow at sonic velocity therethrough at its region of maximum restriction throughout a comparatively wide range of positions of the relatively movable throttle members corresponding to all operating conditions of the engine from idle to near wide open throttle.
Other objects are to provide symmetrical throttle means of the above character for a two barrel carburetor wherein the throttle means for one of the carburetor barrels comprises a fixed orifice member and an axially movable coaxial closure member, and wherein the throttle means for the other carburetor barrel comprises a fixed closure member and an axially movable coaxial orifice member; and to provide such throttle means wherein the forces effected by the fuel flow acting on the movable members in the two carburetor barrels substantially counterbalance each other.